Your posts are hard to decipher -
I think, if you kept my responses in context and quoted them correctly, it would make deciphering a lot easier.
Explain how a reactive force (thrust) is produced when there is no resistance to the free expansion of gas into a vacuum .
The same way - as explained over and over - it is produced, when there is resistance in an atmosphere (or in any other environment).
Thrust is produced (in short) by the chemical reaction of burning fuel; this is completely independent of the environment.
The force and reactive force are between the rocket and the gas (produced by the chemical reaction); where the gas "goes to", vacuum or atmosphere, doesn't really matter.
You say ,correctly in that first sentence above that thrust is produced when there is resistance in an atmosphere or any environment which produces resistance .
What you present out of context is
only part of what I said.
My complete statement (including the question it was an answer to, see underlined passages) is:
"A reactive force (thrust) is produced, when there is no resistance, the same way it is produced, when there is resistance. Vacuum or atmosphere, doesn't really matter"
Therefore the reactive force of thrust is dependent on environment.
How do you get to that conclusion? Please explain.
Saying "a car can accelerate uphill" does not imply it "cannot accelerate downhill"; especially when explicitly stating "a car can accelerate downhill the same way it accelerates uphill".
Second sentence you state otherwise .
No, as explained above, my statement is "rockets create thrust in a vacuum the same way they do in any other environment".
Especially as the one, who has (wrongly) accused me of sophistry, please don't try to read something into my responses, that obviously isn't there.
Thrust is not produced by any chemical reaction , chemical reactions produce thermal energy .
That is - at best - a misleading statement.
- Chemical reactions don't only produce thermal energy; in the case of rockets they produce (at least) thermal energy and (a large amount of) gas.
- Chemical reactions can also consume thermal energy (An endothermic reaction is any chemical reaction that absorbs heat from its environment.)
Thrust is created when a system expels or accelerates mass in one direction; this happens in a rocket and is powered by the chemical reaction of burning rocket fuel.
In a rocket engine this thermal energy increases the pressure inside the chamber which forces the exhaust gas out of the chamber
Again, this is misleading. While increasing the thermal energy of a gas (all other things being equal) does increase its pressure, the important aspect here is, that the chemical reaction creates large amounts of additional gas.
Imagine it as the chemical reaction "pumping
additional gas into the reaction chamber" - this is responsible for a large part of the increased pressure.
where it encounters the resistive pressure of the air .
If there is air - yes. If there isn't, it doesn't make a signifikant difference.
Thrust is produced by resistance to this active force . Thermal energy converts to kinetic energy .
Thrust is produced by accelerating/expelling the gas. Resistance of the environment is not important, because thrust has been created before resistance even becomes relevant.
Thermal energy can be part of the process, but a rocket would function as well, if no heat (thermal energy) was produced.
Please let me encourage you to google "cold gas thruster" (one example
https://en.wikipedia.org/wiki/Cold_gas_thruster)
It is a simple process and thrust has been shown by experiment and observation to be inversely proportional to the area over which the force acts.
Please provide an example of these experiments - I'm not sure what you're trying to convey.
I sounds like you're mixing up pressure and thrust?
Your claim that Joules law doesn't apply to rockets is claptrap as all physical laws apply as shown by all "rocket in a vacuum "video experiments which are really "bomb in a vacuum" vids .
My claim is properly supported by logical deduction. Starting with the fact, that the requirements for Joule's Law are not met by rockets.
Joule's Law requires a closed volume and a constant amount of gas to be apllied correctly - as there is no closed volume (rockets are an open volume => exhaust) and the amount of gas increases (chemical reaction produces additional gas), it does not apply.
=> The videos, that have been posted in this discussion, do not demonstrate Joule's Law.
You could research and show me the definitive experiment that shows a rocket engine working in a vacuum along with the complete physical description but that doesn't exist -
I have already provided a quite detailed description of the physical (and chemical) process.
Thrust is an application of Newton's Laws, which as been proven (as even you confirm).
If you want to dispute Newton's Laws, it is up to
you to provide prove to rebut them.
if it did the joules law wouldn't be a law .
Joule's Law would still be a law and completely unconcerned, as it doesn't apply in the first place.
iC